Under the Lacey Act, it is unlawful to import, export, sell, acquire, or purchase fish, wildlife or plants that are taken, possessed, transported, or sold: 1) in violation of U.S. or Indian law, or 2) in interstate or foreign commerce involving any fish, wildlife, or plants taken possessed or sold in violation of State or foreign law.

The law covers all fish and wildlife and their parts or products, plants protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and those protected by State law. Commercial guiding and outfitting are considered to be a sale under the provisions of the Act.

In 2008, the Lacey Act was amended to include a wider variety of prohibited plants and plant products, including products made from illegally logged woods, for import.

When the Lacey Act was passed in 1900, it became the first federal law protecting wildlife. It enforces civil and criminal penalties for the illegal trade of animals and plants. Today it regulates the import of any species protected by international or domestic law and prevents the spread of invasive, or non-native, species.